Process of refining potash-bearing brines.



' "urriin STACllZS PATENT .IQFFICE.

CLINTON EMERSON IDOLBEAR, 0F IBERKELEY,CALIFORI Q'I1i, ASSIGNOB TO FBANMH.

HITCHCOCK, OF WASHINGTON, DISTRICT 0F COLUMBIA.

PROCESS OF REFINING ror'AsH-nniimne IXRINES.

incense.

Ho Drawing.

T 0 all whom it may concern Be it known that I, CLINTON EMERSON DoLenAn, a citizen of the United States, re siding at Berkeley, in the county of Alameda and State of California, have invented certain new and useful Improvements in Processes of Refining Potash-Bearing Brines, of which the following is a specification.v I My invention relates to methods of separating the more valuable ingredients of potassium-bearing brines from the less valuable ingredients thereof.

The invention, in its broadest aspect, resides in a novel procedure contemplating the separation of the more valuable ingredients of potassium-bearing brine from the less valuable ingredients thereof and in turn separating the separated more valuable salts fromeach other.

The invention, in another aspect, resides in effecting such separation, separating the precipitate from the mother brine, and separating the precipitated salts from each other. i s

My invention is based on the'discovery that if a potassiumbearing brineis treated with'carbon dioxid and with a substance capable of forming an insoluble double salt with potassium and also an insoluble borate, sodium bicarbonate, and insoluble borate and an insoluble double potassium salt are formed and bein insoluble in the solution, precipitate there rem.

My invention, therefore, contemplates a treatment of potassium bearing brines with the substancesstated' and, in certain aspects,

further resides in separating the precipitate from. the mother liquor and by treating the same'vvith water at a suitable temperature the sodium bicarbonate is alone dissolved and can thus be separated from the remaining precipitate and that i'fthis still remaining precipitate be heated at a sufficiently high temperature to decompose the double potassium salt the contained potassiumsalt is alone soluble and can be separat-ed from the precipitate and borax or boric acid can be'recovered from the precipitate.

j Specification of Letters Patent. Application filed January 22, 1913. Serial Ito. M3387.

Patented Apr. 8, i913.

My process is peculiarl adapted for the treatmentoi. the Searles in San Bernardino county, California. It IS llkGWlSG applicable to brines found elsewhere.

In describing how this invention is to be carried into effect, I will take as an example the refining oi brine from Searles Borax Lake. In practice with such a brine, I prefer to use magnesium carbonate as the sub stance capable of forming an insoluble double salt with potassium and also an insoluble borate. This brine is composed oi orax Lake brine an aqueous solution ofsodium chlorid 16.77

per cent, sodium sulfate.5.46 per cent, sodium carbonate 4;.61 per cent, potassium chlorid 4.49 per cent; and sodium tetraborate 1.32 per cent, all of these substances being calculated as anhydrous salts. In. a suitable vessel a given quantity of this brine is,

treated with an excess of 8.5 per cent. of its weight of magnesium carbonate in finely di- The carbon dioxid combines with the so dium carbonate and a portion of water and forms sodium bicarbonate which is only slightly soluble in the solution and is mostly precipitated therefrom. The carbon dioxid also combines with the magnesium carbonate and a portion of water and forms magn'esium bicarbonate which is to considerable extent soluble in the solution and therefore dissolves therein. This dissolved magne sium bicarbonate immediately reacts with the sodium tetral'iorate forming the insoluble magnesium tetra borate and sodium bicarbonate as illustrated by the symbolic" equation The magnesium borate is quite insoluble in the solution and almost completely precipitates therefrom as does the sodium b1- carbonate thus formed. A further portion of the magnesium bicarbonate together perhaps with some normal magnesium carbonate reaots With the potassium chlorid tor n- 100 .vided condition and subjected to the action ing a potassium magnesium carbonate according to the following symbolic illustrations:

aiugco ngucon ench .inoo n co +n ci +eco Just the exact nature of the reaction is impossible to state but the result is the formation of either the double salt normal potassium magnesium carbonate (K CO MgcO or the double salt potassium bicarbonate magnesium carbonate (KHCQMgCOJ or a mixture of both according to the condi: tions of temperature, pressure, etc, under which the reaction takes place. It is imma-- the mother brine' Warm water, not"suificientlyhot to decompose the double potassium magnesium carbonate is added in suflicient quantity t o completely dissolve the contained sodium bicarbonate. This solution is separated from the precipitate by decantation or filtration and the contained carbonate recovered by evaporation or lowering of temperature and crystallization as will be well understood. The remaining precipitate is heated sufliciently highto decompose the' double potassium magnesium carbonate contained therein. This can be done either by heating the dry precipitate or by heating in water at about 100 degrees centigrade or higher. If heated dry it is afterward treated with sufiicient water to completely dissolve the-liberated potassium carbonate or bicarbonate or both. If heated with water sufiicient Water is used or afterward added to completely dissolve the liberated potassium carbonate or bicarbonat 'or both. This solution is separated fronrthe remaining precipitate by decantation filtration and treated by-any of the usual methods such as evaporation or tallization to recover the potassium carbonate therefrom. The'remaining precipitate now contains magnesium, tetra borate' and .ma-gnesium carbonate and as the amount of magnesium carbonate I present is greater thanthe frna gnesium tetra borate it is eco nomica-lly advisable to use the precipitate for,

the treatment of more of the original brine the presence of magnesium boratc being harmless. Vith an equal amount of brine used in the first operation suliicient magnesium carbonate should be added to this remainingprecipitate to replace that which is decomposed in the reactions forming magnesium chlorid and magnesium tetra borate. Atthe end of each cycle of this process the remaining precipitate is richer iii-magnesium borate as all ofthe sodium tetra borate present is converted into sodium, bicarbonate and magnesium tetra boratc. After repeated use the last remaining precipitate will be rich in magnesium tetra borate and is then treated by the usual methods employed in borax or boric acid manufacture from magnesium.borute minerals as will be well understood.

It is to be understood that this invention is not limited to any particular sequence of steps or simultaneous operations or reactions.

Having thus described my invention and a preferred manner of carrying it into p ac:- tice, what I claim and desire to secure by Letters-Patent is:

' 1. The process of recovering the more valuable ingredients from a brine bearing potassium and sodium consisting in trcating the brine with carbon dioxid and with a substance capable of forming an insoluble double salt with potassium.

2. The process of recovering the mre valuable ingredients from a brine bearing potassium and sodium consisting in treating the brine with carbon dioxid and with a substance capable of forming an insoluble double carbonate with potassium.

3. The processof recovering the more valuable ingredients from a brine bearing p0 tassium, sodium and boron consisting in treating the brinewith carbon dioxid and with a substance capable of forming-mi, insoluble doublesaltwith potassium and an insoluble borate.

41912118 process of recovering the more valuable ingredients from j'brine bearing chlorids, sulfates, carbonates 'and boratesoi sodium and potassiumconsistim in treat ing the brine with carbon'dioxi and with a substance capable of torming'insoluble potassium and boron compounds.

5. jifhe procss of recovering the more valuable ingredients. of brine carrying potassium, sodium and boron, consisting in treating the brine wit-lrmagncsium bicarbonate and-carbon di'oxid whereby any-sodium carbonate presentis precipitated as sodium bicarbonate, any soluble borat-e present isde composed and the boric acid radical thereof is precipitated as a magnesium borate, and the potassium sal t present is decomposed, the potassium thereof forming a potassium carbonate and joining with a magnesium carbonate and precipitating as a double p0 tassium magnesium carbonate.

6. The process of recovering the more valuable ingredients of brine bearing potas sium, sodium'and boron consisting in treat-- ing the brine With magnesium carbonate and carbon dionid in excess of the amount required to convert the magnesium carbonate into magnesium bicarbonate, whereby any sodium carbonate present is precipitated as sodium bicarbonate, any soluble borate present is decomposed and the boric acid radical thereof is precipitated as a magnesium borate, and the potassium salt present is decomposed, the potassium thereof formiug a potassium. carbonate and joiningnvith a magnesium carbonate and precipitating as a double potassium. magnesium carbonate.

7. The process of refining brine carrying potassium and sodium compounds consisa ing in subjecting the brine to the action of a magnesium carbonate and carbon dioxi'd.

8. The process of recovering the more *aluable ingredients of brine bearing potassiiun, sodium and boron, consisting in treating the brinewith magnesium bicarbonate and carbon dioxid whereby any sodium carbonate present is precipitated as sodium bicarbonate, any soluble borate present is decomposed and the boric acid radical thereof is precipitated as a'magnesium borate, and the potassium salt prescut is decomposed, the potassium thereof forming a potassium carbonate and joining with a magnesium carbonate and precipitating as a double potassium magnesium carbonate separating the precipitated salts from the mother liquor, treating the precipitated salts with water not sufliciently Warm to decompose the double potassium magnesium carbonate, whereby the sodium bicarbonate aione is dissolved, separating the dissolved sodium bicarbonate from the remaining precipitate, heating the remaining precipitate sutiiciently high to decompose the double potassium magnesium carbonate, dissolving the liberated potassium carbonate in Water, separating the dissolved potassiunr carbonate from the remaining precipitate and treating the remaining precipitate to remove a boron compound therefrom.

9. The process of recovering the more valuable ingredients of potassium-bearing ur ne, consisting in treating the brine with magnesium bicarbonate and an excess of carbon dioxid whereby any sodium carbonate present is precipitated as sodium bicarbonate, any soluble borate present is decome posed and the boric acid radical thereof is Waterv not sufficiently Warmto decompose the double potassium magnesium carbonate, whereby thesodium bicarbonate alone is dissolved, separating the dissolved sodium bicarbonate from the remaining precipitate, heating the remaining precipitate sutliciently high to decompose the double potassium magnesium carbonate, dissolving the liberated potassium carbonate in Water, separating the dissolved potassium "carbon ate from the remaining precipitate and treating the remaining precipitate to remove boraX therefrom.

10. The process of recovering sodium carbonate, sodium borate and soluble potassium compounds from brines containing them in solution together With sodium chlorid and sodium sulfate, consisting intreating the brine with magnesium bicarbonate and carbon dioXid. whereby the sodium carbonate is precipitated as sodium bicarbonate, the borate decomposed and precipitated as magnesium borate and the potassium of the potassium salt is precipitated as a double potassium magnesium carbonate, separating the precipitate from the mother brine and separating the precipitated mixed salts from each other.

11. The method of recovering sodium carbonate, borax and soluble potassiunrcompounds from brine containing. them in solution together with sodium chlorld and sodium sulfate, consisting in treating the brine with magnesium bicarbonate and carbon dioxid, separating the precipitate from the remaining brine, treating the precipitate 'With water to dissolve the sodium iaicarbonate, separating the precipitate from the dissolved sodium bicarbonate, heating the precipitate to a temperature sufficiently high to decompose the double magnesium potassium carbonate, dissolving the liberated potassium carbonatein Water and lastly recovering the boric acid radical of the magnesium borate.

In testimony whereof I atlix my signature in presence of tWo itnesses.

GLlNTON EMERSON DOLBEAR. Witnesses EDMUND H. PARRY, A. M. Panama, 

